For an emergency situation (danger to life or property or a crime in progress) call 911.
For a non-emergency report, call 503-823-3333. It's a menu system that should lead to a live person. This assures a report is logged in Multnomah County.
For after-the-fact complaints, emails are best. These should be sent to email@example.com. These emails are logged. Photos are helpful if you have them.
Keep in mind that the Holgate Channel No Wake Zone is from the mouth of the Ross Island Lagoon south to the end of the floating homes. The north Holgate Channel is not a wake free zone. Make sure that your boat is where it is supposed to be in the channel and that rules of the road are being followed by you and/or your crew.